The invention relates to a fluid ring compressor having a first compression stage, which has a first impeller eccentrically mounted in a housing, and a second compression stage, which has a second impeller eccentrically mounted in a housing. Both compression stages are single-acting. A sealing gap separates the first compression stage from the second compression stage.
In fluid ring compressors, a fluid ring is kept in motion by the impeller, with the result that the chambers between the blades of the impeller are closed off by the fluid ring. Since the impeller is mounted eccentrically in the housing, the fluid ring penetrates by different amounts into the chamber, depending on the angular position of the impeller, and thereby acts as a piston which changes the volume of the chamber. In the angular range in which the volume of the chamber is small, the gas to be compressed enters the chamber. As the impeller is rotated, the volume of the chamber decreases and the compressed gas emerges again in a different angular position of the impeller at the end of the compression process.
By connecting a plurality of compression stages in series in a compressor, it is possible to produce an increased pressure difference between the inlet side and the outlet side of the compressor. The gas drawn in on the inlet side is compressed by the first compression stage. From the outlet side of the first compression stage, the gas passes to the inlet side of the second compression stage so as to be compressed further there.
If the first compression stage and the second compression stage are separated from one another only by a sealing gap, very compact construction of the fluid ring compressor is possible.
However, a leakage flow through the sealing gap can arise owing to the pressure difference between the first compression stage and the second compression stage. Such a leakage loss has a negative effect on the efficiency of the compressor.